Select the best explanation of how a t cell uses either cell-to-cell contact or chemical signaling to enhance the activities of the immune system.
a. chemicals called cytokines are secreted from t cells to signal production of antibodies by b cells.
b. the second exposure of the antigen causes the t cell to activate memory t cells.
c. the pathogen is engulfed by a t cell and its antigenic markers are displayed on its surface.
d. the t cell stimulates the antigen-presenting cell to release chemicals called cytokines to stimulate the cytotoxic t cells.

good one: produce hormones that plants grow.

bad one: the problem with organic matter is that while plant nutrients are needed for crop growth, they can also stimulate excessive growth of the wrong plants – mainly, algae.

events in order:

1.       vishnu schist

2. zoroaster granite

3. bass limestone

4. hakatar   shale

5. igneous intrusion

6. shinumo quartzite

7. dox sandstone

8. tapeats limestone

9. bright angel shale

10. muav limestone

11. temple butte limestone

12. redwall limestone  

nonconformity

answer: the unkar group shows angular unconformity because the layers are turned at angle.

unconformity

answer: specifically the angular unconformity occurs between the cambrian and precambrian rocks. the dox sandstone, shinumo quartzite, hakatar shale, and bass limestone have been filled. an angular unconformity occurs between the cambrian and precambrian rocks. the dox sandstone, shinumo quartzite, hakatar shale, and bass limestone have been filled.

disconformity

answer: the disconformities aremarked irregular lines between the sedimentaryrocks layers.